The Simple Science of Flight:
From Insects to Jumbo Jets

Henk Tennekes

Unlike most works of popular science, The Simple Science of Flight
doesn't shy from equations and simple algebra. It also uses units such
as newtons and joules and assumes a basic understanding of vectors (for
simple force triangles). Anyone with high school physics should be able
to follow it without problems, however, and it wouldn't be a bad choice
for someone wanting to learn some simple physics. Tennekes uses examples
from everyday life to help illustrate physical concepts and units, and
he writes about flight quite generally, treating insects, birds, and
aircraft (powered and unpowered) together. Simple but attractive ink
drawings complement the text.

The Simple Science of Flight begins with the relationship between wing
size, weight, and speed. This is embodied in a "Great Flight Diagram",
which plots weight against cruising speed. It goes on to look at the
power requirements of flight and the "nutritional" requirements of birds
and aircraft. The energy values of different fuels and the efficiencies
of various forms of transport are compared — have you ever wondered how
a budgie stacks up against a Porsche or a 747 when it comes to energy
per unit weight per metre travelled?

Wind and weather affect everything that flies. Slope soaring and the use
of thermals are important for both soaring birds and hang-gliders; strong
winds can play havoc with the migrations of birds and the scheduling
of airline flights; and wind direction is a major issue at take-off
and landing. The critical ratio between lift and drag (the glide ratio
or "finesse") is illustrated in the "Great Gliding Diagram", plotting
rate of descent against airspeed. The aerodynamics behind this explain
why the slenderness (aspect ratio) of wings matters, and why hovering
(in the fashion of hummingbirds) is so inefficient.

A chapter on "flying playthings" covers ultralights and sailplanes, the
design of paper airplanes, and the history of human-powered aircraft.
And the final chapter is a hymn of praise to the Boeing 747, which
Tennekes considers one of the great engineering wonders of the world.
He argues that it fits perfectly into a niche created by the constraints
of physics and engineering (and of air temperature and density) on the
one hand and the practical realities of commercial aviation on the other.

Reading the The Simple Science of Flight was pure pleasure. It is
clear and readable without being at all patronising, and should be
enjoyed by everyone from school students and bird-watchers to physics
and engineering graduates.